Detailed process of implementing the 2048 mini game in WeChat applet

 // Construct an empty matrix [[null,..,size.length],[]]
    empty: function() {
        var cells = [];

        for (var x = 0; x < this.size; x++) {
            var row = cells[x] = [];

            for (var y = 0; y < this.size; y++) {
                row.push(null);
            }
        }

        // [[{x:0,y:0},{x:0,y:1}],[]]
        return cells;
    },

   // Randomly select a cell from the empty cells randomAvailableCell: function() {
    
    // Get the fillable grid coordinates availableCells: function() {
    
    // Is there an empty cell cellsAvailable: function() 
    
    /* 
     * Get cell content * @param {object} cell {x:0,y:0} cell coordinates */
    cellContent: function(cell) {

 // Initialize data addStartTiles: function() {
        for (var x = 0; x < this.startTiles; x++) {
            this.addRandomTiles();
        }
    },

    // Randomly fill a random cell with 2 or 4
    addRandomTiles: function() {

        if (this.grid.cellsAvailable()) {
            var value = Math.random() < 0.9 ? 2 : 4;
            var cell = this.grid.randomAvailableCell();
            var tile = new Tile(cell, value);
            this.grid.insertTile(tile); // insert a cell}

    },

touchStart: function(events) {

        // Multi-finger operation this.isMultiple = events.touches.length > 1;
        if (this.isMultiple) {
            return;
        }

        var touch = events.touches[0];

        this.touchStartClientX = touch.clientX;
        this.touchStartClientY = touch.clientY;

    },

    touchMove: function(events) {
        var touch = events.touches[0];
        this.touchEndClientX = touch.clientX;
        this.touchEndClientY = touch.clientY;
    },

    touchEnd: function(events) {
        if (this.isMultiple) {
            return;
        }

        var dx = this.touchEndClientX - this.touchStartClientX;
        var absDx = Math.abs(dx);
        var dy = this.touchEndClientY - this.touchStartClientY;
        var absDy = Math.abs(dy);

        if (Math.max(absDx, absDy) > 10) {
            var direction = absDx > absDy ? (dx > 0 ? 1 : 3) : (dy > 0 ? 2 : 0);

            var data = this.GameManager.move(direction) || {
                grids: this.data.grids,
                over: this.data.over,
                won: this.data.won,
                score: this.data.score
            };

        }